Suction assisted endless belt separator

ABSTRACT

A device is disclosed for feeding sheets to a sheet processing machine, such for example, as to a folding and pasting machine. The novel feeding mechanism includes at least one conveyor having at least one endless belt. The endless belts are intermittently advanced to carry one sheet at a time taken from a pile disposed above the belt or belts. The intermittent advancement of the belt or belts is brought about through a one-way clutch coupling a drive pulley to a crank arm which is oscillated back and forth through a link mechanism driven by a continuously rotating drive wheel. The machine to which the sheets are successively fed includes a pair of pressure feed rollers to which the leading edge of each sheet is moved. After the sheet is grasped by the feed rollers, further movement of the sheet continues the advancement of the belt while the belt drive roller is freewheeling. The belt has a large number of perforations and a vacuum chamber is located below the belt over a region representing a substantial forward portion of the pile of sheets.

United States Patent [191 J aton Sept. 23, 1975 SUCTION ASSISTED ENDLESSBELT SEPARATOR [75] inventor: Jean-Philippe Jaton,Chapelle,

Primary ExaminerRichard A. Schacher Assistant ExaminerBruce H. Stoner,Jr.

Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman,Chiara & Simpson [5 7] ABSTRACT A device is disclosed for feeding sheetsto a sheet processing machine, such for example, as to a folding andpasting machine. The novel feeding mechanism includes at least oneconveyor having at least one endless belt. The endless belts areintermittently advanced to carry one sheet at a time taken from a piledisposed above the belt or belts. The intermittent advancement of thebelt or belts is brought about through a one-way clutch coupling a drivepulley to a crank arm which is oscillated back and forth through a linkmechanism driven by a continuously rotating drive wheel. The machine towhich the sheets are successively fed includes a pair of pressure feedrollers to which the leading edge of each sheet is moved. After thesheet is grasped by the feed rollers, further movement of the sheetcontinues the advancement of the belt while the belt drive roller isfree-wheeling. The belt has a large number of perforations and a vacuumchamber is located below the belt over a region representing asubstantial forward portion of the'pile of sheets.

5 Claims, 4 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of23,907,278

US Patent Sept. 23,1975 Sheet 2 of2 3,907,278

SUCTION ASSISTED ENDLESS BELT SEPARATOR FIELD OF THE INVENTION Sheetfeeding devices have been known in the past which have at least one stopagainst which there bears a pile of sheets placed on at least oneconveyor belt and have also included means permitting the separation ofthe sheets one by one and their introduction into the machine in a givenrhythm which can be checked. Such a device is described in Swiss Pat.No. 424,448 and Swiss Pat. No. 493,396.

It is also known in the art to use an endless belt machine such as abovedescribed which is perforated and which is displaced in a cavity inwhich a reduced pressure is created. Such a device is disclosed inGerman Patent Application No. 1,925,179.

In devices of the type above referred to, it has been noted that at themoment of departure of the sheet a slip occurs between the conveyor beltand the printed side of the sheet. This friction has been a source ofsoiling of the belt by the printing ink of the sheet, and it has alsobeen noted that the departure of the sheet can not be controlledaccurately. Both of the above aspects of the prior art machines referredto are a distinct disadvantage.

BRIEF SUMMARY OF THE PRESENT INVENTION The present invention provides anovel sheet feeding machine which overcomes the above disadvantages.Specifically, the present invention provides a sheet feeding device ofthe type having at least one endless belt, which is intermittentlyadvanced to carry one sheet at a time from a pile disposed above thebelt or belts. The intermittent advancement of the belt or belts isbrought about through a one-way clutch coupling a drive pulley to acrank arm which is oscillated back and forth through a link mechanismdriven by a continuously rotating drive wheel. The machine to which thesheets are successively fed includes a pair of pressure feed rollers towhich the leading edge of each sheet is moved. After the sheet isgrasped by the feed rollers, further movement of the sheet continues theadvancement of the belt while the belt drive roller is freewheeling. Thebelt has a large number of perforations and a vacuum "chamber is locatedbelow the belt over a region representing a substantial forward portionof the pile of sheets.

More specifically, the present device is characterized in that itcomprises a shaft for driving the drive pulley which includes auni-directional coupling means between the drive shaft and the drivepulley. It also includes means for driving the shaft by imparting analternating rotary movement thereto in such a manner that the belt isonly driven by the drive pulley in one direction, and hence once thesheet has been grasped by the conveying means of the machine to whichthe sheet is to be fed, the sheet drives the belt and consequently thepulley, which free-wheels. The feeding device further includes means forbraking the belt after the sheet grasped by the conveying means of theprocessing machine has left the belt.

Thus, once the sheet is grasped by the sheetconveying means of themachine, the endless belt no longer intervenes in an active manner butbecomes passive, and any slipping between the sheet and the endless beltis eliminated. Since the endless belt, which tends to continue itsdisplacement because of its inertia and the inertia of the pulley, isbraked, untimely entrainment of the following sheet is avoided.

THE DRAWINGS The accompanying drawings illustrate, by way of example, apreferred embodiment of the present invention.

FIG. 1 is a diagrammatic side view, in section, thereof.

FIG. 2 is a diagrammatic view in section as taken along line II-II ofFIG. 1.

FIG. 3 is a diagrammatic view in section as taken along line IIIIII ofFIG. 1.

FIG. 4 illustrates, diagrammatically, a modified form of the presentinvention.

DETAILED DESCRIPTION The feeding device illustrated in the drawingscomprises one or more endless belts I, placed side by side according tothe width of the sheets to be introduced and having perforations 2. Thesheets for which the present feeding device is particularly adapted foruse are cardboard. This endless belt 1 is guided by rollers 3 and 4, atransmission pulley 5 and a tension roller 6 which is displaceable andcan be locked in position in such a manner as to ensure a suitabletension of the endless belt 1. The endless belt] is further supported bythree rollers 8 and by a vacuum chamber 10 fixed to a cross-bar 12. Apermanent reduced pressure is created in the vacuum chamber l0v by meansof a vacuum source (not illustrated) connected by a flexible pipe 13 toa pipe 14 of the vacuum chamber 10. This chamber 10 is illustrated incross section'in FIG. 3. It is fixed to the cross-bar 12 by screws 57and has, in its upper portion and over its whole length, an opening 59which covers the endless belt 1, held in permanent contact with theupper portion 10a of the chamber 10, the perforations 2 being displacedopposite the opening 59.

The rollers 3, 4, 6 and 8, the transmission pulley 5 and the cross-bar12 are fixed to a vertical plate 15, itself fixed to a transverse beam21, connecting two supports 23 and 24 (FIG. 2) by means ofa fixing andlocking device 16 comprising a pin' 17 one of the ends of whichcomprises an eccentric 18 to which is fixed a ball bearing 19, the otherend being equipped with a knurled knob 20 serving to actuate the device16. A locking handle 61 locks the pin 17 in its position of use. Thus,by turning the knurled'knob 20, it is possible, through the action ofthe eccentric 18, to position the plate 15 and the members which arefixed thereto, laterally in a very precise manner-,in relation to thesupports. The transmission pulley' 5 is mounted on a drive shaft 28extending between two vertical supports 23 and 24 (FIG. 2).

A pile of sheets of cardboard 7 is illustrated, bearing on the one handagainst the endless belt 1 and on the other hand, at the front, againsta'gauge 9, known per se. This gauge is adjusted in such a manner as toleave a space 11 corresponding to the thickness of one sheet betweenitself and the endless belt 1. At the rear, the pile of sheets ofcardboard 7 rests on at least one roller 38 fixed to the end of anadjustable arm 39 held in a rectangular U-shaped bracket 40 fixed to ahorizontal transverse bar 41, rigidly connected to the support on whichthe bracket 40 can slide and be locked in the desired position by meansof a screw 43, while the arm 39 can be fixed in the desired position onthe bracket 40 by means of a locking screw 42. These members are knownfrom the earlier devices. The sheet 7a, which is being fed, isillustrated resting entirely on the endless belt.

Likewise illustrated diagrammatically, in front of the gauge 9, are twodrive rollers 33 and 34 representing the sheet-conveying means of themachine processing these sheets.

The transmission pulley is mounted on the one hand on a ball bearing(FIG. 2) and on the other hand on a one-way clutch or unidirectionalcoupling device 26 of the free-wheel type, of any design well known perse. Such a clutch is exemplified as comprising an inner ring 26a and anouter ring 26b, rigidly connected to one another for rotation in onedirection of rotation by wedging of the tapered rollers 35. The ring 26aand the inner ring of the bearing 25 are driven onto a sleeve 27positioned on the shaft 28 by a key 29. On the other hand, the sleeve 27passes through the plate 15 in which it can rotate in a ball bearing 53.The sleeve 27 is held axially on the plate 15 on one side by a splitresilient ring 56 and on the other by a spacing ring 55. The drive shaft28 is positioned and held in the supports 23 and 24 by ball bearings 44and 45, the ball bearing 44 being held between two split rings 50 and50', while the ball bearing 45 is held between two split rings 52 and52. On the other hand, the shaft 28 has a journal 46 locked laterally inthe ball bearing 44 by means of a sleeve 47, a supporting washer 48 andthe crank 30, the whole being secured by a split ring 49. The otherjournal 51 of the shaft 28 is mounted free in the ball bearing 45 so asto permit the axial expansion of the shaft.

Fixed to the journal 46 of the shaft 28 is a crank keyed onto the shaftby a key 29 (FIG. 1). This crank 30 carries a crank-pin 58 on whichthere is articulated the end of a connecting rod 31, the other end ofwhich is articulated on an eccentric crank-pin 36 of a wheel 32.

The device operates as follows:

The wheel 32 is driven with a continuous rotational movement in thedirection of the arrow F1, the speed of rotation being adapted to theworking rhythm of the machine processing the sheets, that is to say tothe speed of rotation of the drive rollers 33 and 34. The effect of therotation of the wheel 32 is to impart to the crank 30 a movement whichoscillates between the two extreme positions 58' and 58" of thecrank-pin 58. The corresponding positions of the connecting rod 31 andof the crank-pin 36 are illustrated by the broken lines 31 and 31", and36 and 36", respectively. The are 58-58 is such that the correspondingarc A-B measured on the drive pulley 5 is slightly greater than thedistance separating the front face 9a of the gauge 9 from the verticalplane passing through the axes of the rollers 33 and 34 and through theline of contact 60 of these.

The wheel 32 drives the crank 30 in the direction of the arrow F2 whenthe crank-pin 36, starting from the position 36', turns in the directionof the position 36.

In this direction of rotation of the crank 30, the transmission pulley 5is driven in rotation by means of the unidirectional coupling 26. On theother hand, the pul ley 5 is not driven when the crank 30 is turning inthe opposite direction to the arrow F2, that is to say when thecrank-pin 36 is turning from the position 36" to the position 36.

The moment when the endless belt 1 is not being driven, whichcorresponds to the rotation of the crank 30 in the opposite direction tothe arrow F2, will be considered first. At this moment, the lower sheet7a of the pile 7 is drawn against the endless belt 1 by the vacuumacting through the perforations 2 in the endless belt. When the crank 30leaves the position 58', the endless belt is driven inthe direction ofthe arrow F3, and with it the sheet 7a. FIG. 1 illustrates the deviceand the sheet in an intermediate position, the front end of sheet 7ahaving arrived half way between the gauge and the drive rollers 33 and34 and having already left the endless belt 1.

Before the crank-pin 58 reaches the position 58", the front end of thesheet 7a is grasped by the rollers 33 and 34 turning in the direction ofthe arrows F4 and F5. These rollers are driven at a linear speedsubstantially higher than the speed of the endless belt 1, so that theendless belt is no longer driven by the pulley 5 but by the sheet 7a, byfriction without slip, the pulley 5 being driven in free rotation by theendless belt 1. This free rotation of the pulley 5 is rendered possibleby the unidirectional coupling 26. The sheet 7a grasped by the rollers33 and 34 is illustrated in chain line at 7a.

When the sheet 7a leaves the endless belt 1, this tends to continue itsmovement because of its own inertia and that of the pulley 5.Nevertheless, the endless belt is rapidly braked by the action of thevacuum chamber 10 on the belt and the friction inherent in the mechanismdescribed. The total stopping of the endless belt 1 takes place shortlybefore the crank-pin 36 reaches position 36'. From this moment on, thetransmission pulley 5 is again kinematically rigidly connected to thecrank 30 and drives the belt which carries along a fresh sheet. Theposition of the roller 38 is adjusted in such a manner that when therear edge of the sheet 7a passes under the gauge 9, the following sheetdrops onto the endless belt which, at that moment, is substantiallystopped.

FIG. 4 illustrates, diagrammatically, a modified form of embodiment ofthe device showing how it is possible to mount two endless-belt devices,as illustrated in FIG. 1, one behind the other in such a manner as toensure better operational conditions for relatively long sheets, ifnecessary. The members of the second device bear the same referencenumerals accompanied by a prime.

From the operation described above it is clear that the transmissionpulley 5 is driven at a precise moment, corresponding to the point 58,this driving being ensured by a simple and precise mechanism. Thedeparture of the sheet is therefore ensured strictly, which enables thefollowing members of the machine to be simplified, which, whenconventional devices are used for the introduction of sheets, have toensure, by other means, such as a chain register, the advance of thesheets at precise moments, in synchronism with the sequential workingphases of the machine.

The device described comprises a perforated belt and a vacuum chamber,but the perforation and this vacuum chamber are not absolutely essentialto ensure the entrainment of the sheets.

Moreover, the braking of the endless belt may be effected by other meanssuch as a vacuum chamber, which may or may not be an auxiliary one,acting on an unperforated portion of the endless belt, or a mechanicalbrake acting directly on the belt or on the shaft of the transmissionpulley.

I claim as my invention:

1. A device for feeding a sheet processing machine having asheet-conveying means, said device comprising at least one endless beltconveyor positioned to feed sheets successively to said sheet-conveyingmeans, said endless belt conveyor having an upper reach disposedgenerally in a horizontal plane, a drive pulley for intermittentlyadvancing the upper reach of said belt toward said sheet conveyingmeans, said belt being adapted to entrain, one by one, sheets taken froma pile disposed above said belt conveyor to bring the front edge of asheet to said sheet-conveying means, means for causing a sheet to beheld to said belt until withdrawn therefrom by said sheet-conveyingmeans, a drive shaft, a unidirectional coupling means between said shaftand said drive pulley, and means for oscillating said drive shaft, saidbelt being only driven by said drive pulley in one direction until thefront edge of a sheet has been grasped by said sheet-conveying means,said sheetconveying means causing further advance of said belt untilsaid sheet is drawn off of said belt, and means for braking the beltthereafter until the start of advancement of the next sheet by saiddrive pulley being directly coupled to said drive shaft to initiate anew cycle of sheet advancement.

2. A device according to claim 1, in which said endless belt conveyor isperforated, and in which suction means is disposed on the under side ofsaid upper reach in proximity to the delivery end'of said sheets.

3. A device according to claim 2, in which a plurality of supportingrollers are disposed below the upper reach of said endless belt conveyorremote from the delivery end thereof.

4. In a machine for processing sheets, which machine includes matingdriven sheet advancing rolls which advance a sheet at a predeterminedspeed when the sheet is gripped by said rolls; a device for feedingsheets cyclicly to said rolls comprising an endless belt conveyor; meanssupporting said endless belt conveyor below a stack of sheets to be fed;a drive pulley for partially advancing a sheet toward said mating rollsat a speed less than the speed at which a sheet is advanced by saidmating rolls; said endless belt conveyor being partially wrapped aroundsaid drive pulley; a drive shaft; a oneway clutch connecting said drivepulley to said drive shaft; crank means for oscillating said drive shaftback and forth; said endless belt being advanced first by said drivewheel during one direction of oscillation of said drive shaft until asheet is grasped by said sheet advancing rolls, said belt conveyor beingfurther advanced by the pull of said advancing sheet on said endlessbelt conveyor, said belt conveyor being free to further advance by thefree-wheeling of said drive wheel on said drive shaft, and brake meansfor stopping said belt conveyor after the rear edge of said belt leavessaid belt conveyor.

5. A device according to claim 4, in which said endless belt conveyor isperforated and in which a suction box is disposed immediately below aportion of the upper reach of said endless belt conveyor adjacent thesheet delivery and thereof.

1. A device for feeding a sheet processing machine having asheet-conveying means, said device comprising at least one endless beltconveyor positioned to feed sheets successively to said sheet-conveyingmeans, said endless belt conveyor having an upper reach disposedgenerally in a horizontal plane, a drive pulley for intermittentlyadvancing the upper reach of said belt toward said sheet conveyingmeans, said belt being adapted to entrain, one by one, sheets taken froma pile disposed above said belt conveyor to bring the front edge of asheet to said sheetconveying means, means for causing a sheet to be heldto said belt until withdrawn therefrom by said sheet-conveying means, adrive shaft, a unidirectional coupling means between said shaft and saiddrive pulley, and means for oscillating said drive shaft, said beltbeing only driven by said drive pulley in one direction until the frontedge of a sheet has been grasped by said sheet-conveying means, saidsheet-conveying means causing further advance of said belt until saidsheet is drawn off of said belt, and means for braking the beltthereafter until the start of advancement of the next sheet by saiddrive pulley being directly coupled to said drive shaft to initiate anew cycle of sheet advancement.
 2. A device according to claim 1, inwhich said endless belt conveyor is perforated, and in which suctionmeans is disposed on the under side of said upper reach in proximity tothe delivery end of said sheets.
 3. A device according to claim 2, inwhich a plurality of supporting rollers are disposed below the upperreach of said endless belt conveyor remote from the delivery endthereof.
 4. In a machine for processing sheets, which machine includesmating driven sheet advancing rolls which advance a sheet at apredetermined speed when the sheet is gripped by said rolls; a devicefor feeding sheets cyclicly to said rolls comprising an endless beltconveyor; means supporting said endless belt conveyor below a stack ofsheets to be fed; a drive pulley for partially advancing a sheet towardsaid mating rolls at a speed less than the speed at which a sheet isadvanced by said mating rolls; said endless belt conveyor beingpartially wrapped around said drive pulley; a drive shaft; a one-wayclutch connecting said drive pulley to said drive shaft; crank means foroscillating said drive shaft back and forth; said endless belt beingadvanced first by said drive wheel during one direction of oscillationof said drive shaft until a sheet is grasped by said sheet advancingrolls, said belt conveyor being further advanced by the pull of saidadvancing sheet on said endless belt conveyor, said belt conveyor beingfree to further advance by the free-wheeling of said drive wheel on saiddrive shaft, and brake means for stopping said belt conveyor after therear edge of said belt leaves said belt conveyor.
 5. A device accordingto claim 4, in which said endless belt conveyor is perforated and inwhich a suction box is disposed immediately below a portion of the upperreach of said endless belt conveyor adjacent the sheet delivery andthereof.